Different Types Of Pollutants Research Articles

Association between Air Pollution and Physical Activity and Sedentary Behavior among Adults Aged 60 Years or Older in China: A Cross-Sectional Study.

Exposure to air pollution is associated with an increased risk of all-cause mortality in older adults. Promoting physical activity (PA) and avoiding sedentary behavior (SB) serve as key strategies to maintain and improve human health. However, ambient air pollution can adversely affect PA and SB, increasing the risks of health problems. This study aimed to visualize national spatial patterns of average AQI concentration, PA, and SB distributions and to examine the associations between air pollution and PA and SB in a national sample of Chinese older adults aged 60 years or older. We analyzed the data of the China Longitudinal Aging Social Survey 2020 (CLASS 2020), which sampled 11,399 older men and women from 30 cities in China. Moderate, vigorous, and light PA and SB were measured using the Chinese version of the International Physical Activity Questionnaire-Short Form (IPAQ-C). The environmental measures included the average hourly air quality index (AQI), PM2.5, PM10, and NO2 (µg/m3). The data were analyzed using multivariable linear regression. Increases in the standard deviations (±SD) of AQI, PM2.5, PM10, and NO2 concentrations were associated with decreases in MVPA per week of -2.34 (95%CI = -3.36, -1.32), -2.58 (95%CI = -3.61, -1.55), -1.96 (95%CI = -3.05, -0.08), and -1.19 (95%CI = -2.06, -0.31) and decreases in LPA per week of -6.06 (95%CI = -7.15, -4.97), -4.86 (95%CI = -5.88, -3.85), -4.78 (95%CI = -5.89, -3.68), and -4.59 (95%CI = -5.57, -3.61) h/week, respectively. Increases in one SD of AQI, PM2.5, PM10, and NO2 were associated with increases in SB per week of 1.32 (95%CI = 0.77, 1.88), 0.62 (95%CI = 0.09, 1.14), 1.03 (95%CI = 0.48, 1.59), and 0.98 (95%CI = 0.46, 1.49) h/week, respectively. The spatial distributions of the average AQI concentration, MVPA, LPA, and SB are useful and allow environmental and health policymakers to identify the areas with the highest priority air pollution environmental equality concerns. AQI was positively associated with MVPA and LPA, and it was negatively associated with SB among older adults. AQI, PM2.5, PM10, and NO2 were hardly associated with women's average time spent engaged in MVPA. Region-specific and multi-level health policy options are needed to reduce ambient air pollution by taking different types of pollutants into account in order to avoid changes in PA and SB in this population, especially in locations with high air pollution concentrations.

Microalgal-induced remediation of wastewaters loaded with organic and inorganic pollutants: An overview

The recent surge in industrialization has intensified the accumulation of various types of organic and inorganic pollutants due to the illegal dumping of partially and/or untreated wastewater effluents in the environment. The pollutants emitted by several industries pose serious risk to the environment, animals and human beings. Management and diminution of these hazardous organic pollutants have become an incipient research interest. Traditional physiochemical methods are energy intensive and produce secondary pollutants. So, bioremediation via microalgae has appeared to be an eco-friendly and sustainable technique to curb the adverse effects of organic and inorganic contaminants because microalgae can degrade complex organic compounds and convert them into simpler and non-toxic substances without the release of secondary pollutants. Even some of the organic pollutants can be exploited by microalgae as a source of carbon in mixotrophic cultivation. Literature survey has revealed that use of the latest modification techniques for microalgae such as immobilization (on alginate, carrageena and agar), pigment-extraction, and pretreatment (with acids) have enhaced their bioremedial potential. Moreover, microalgal components i.e., biopolymers and extracellular polymeric substances (EPS) can potentially be exploited in the biosorption of pollutants. Though bioremediation of wastewaters by microalgae is quite well-studied realm but some aspects like structural and functional responses of microalgae toward pollutant derivatives/by-products (formed during biodegradation), use of genetic engineering to improve the tolerance of microalgae against higher concentrations of polluatans, and harvesting cost reduction, and monitoring of parameters at large-scale still need more focus. This review discusses the accumulation of different types of pollutants into the environment through various sources and the mechanisms used by microalgae to degrade commonly occurring organic and inorganic pollutants.

Hierarchical fabrication of GO@Dy2MoO6 heterojunction for catalytic performance and effective wastewater treatment

In this study, a novel graphene oxide/dysprosium molybdate (GO@Dy2MoO6) photocatalyst was successfully prepared via ultrasonic treatment. Under visible light, GO-doped Dy2MoO6 nanocubes showed a better and more cost-effective way to catalyze the photo decolorization of different types of pollutants by RhB, Cr (VI), OFX, and MP. Various analytical methods were used to investigate the produced catalyst. As a result of the decoration of the GO matrix with cubic-like Dy2MoO6, the photocatalytic property was enhanced, the results demonstrated. This composite shown exceptional photocatalytic efficacy and effective separation of photogenerated charge carriers during photodegradation. Subsequently, the reaction diminished totally in 30–60 min, respectively. Even after the fifth recycle, the photocatalyst maintained remarkable stability. Owing to capture experiments, the most active sites and species causing the degradation process are OH and •O2– As a result, the unique GO@Dy2MoO6 photocatalyst was a promising material in the waste water treatment system.

Effect of Metacognitive Instructional Strategy Using PEEDA on Biology Students Achievement in Delta State

The purpose of this research was to determine whether and how a metacognitive educational technique based on PEDDA (Prior knowledge, Exploration, Discussion, Dissatisfaction, and Application) will improve the performance of secondary school biology students in Delta State. The investigation was guided by three hypotheses and three research questions. The research used a quasi-experimental design with a non-equivalent pre-post test and control group setup. Students from the public secondary schools in the three (3) senatorial districts of Delta State were included in the research. A total of 30,813 SS II biology students and 436 overall participated. This research employed a sample of 300 SS II biology students and six biology professors from six different high schools in Delta State. Data was gathered using the researcher’s primary instrument, the Meta-Cognitive Biology Achievement Test (MBAT). Students in the experimental group were taught the biology concepts of “pollution,” “exploration of the different types of pollution,” “discussion on the causes of pollution as well as the effects of pollution,” “dissatisfaction with the experience,” and “application of the control measures for pollution” using a metacognitive instructional strategy, while students in the control group were taught using the lecture method. Statistical methods such as analysis of variance (ANOVA), analysis of covariance (ANCOVA), and mean and standard deviation (SEM) were used to compile and interpret the results (ANCOVA). It was shown that the metacognitive approach to teaching was more effective than the traditional lecture format. Furthermore, the research indicated that while using the metacognitive teaching technique, there was no statistically significant difference in the mean accomplishment scores of male and female students (PEDDA). The study’s results led to many recommendations, including the adoption of metacognitive teaching tactics by secondary school biology instructors to increase student engagement.

Green and Superior Adsorbents Derived from Natural Plant Gums for Removal of Contaminants: A Review.

The ubiquitous presence of contaminants in water poses a major threat to the safety of ecosystems and human health, and so more materials or technologies are urgently needed to eliminate pollutants. Polymer materials have shown significant advantages over most other adsorption materials in the decontamination of wastewater by virtue of their relatively high adsorption capacity and fast adsorption rate. In recent years, "green development" has become the focus of global attention, and the environmental friendliness of materials themselves has been concerned. Therefore, natural polymers-derived materials are favored in the purification of wastewater due to their unique advantages of being renewable, low cost and environmentally friendly. Among them, natural plant gums show great potential in the synthesis of environmentally friendly polymer adsorption materials due to their rich sources, diverse structures and properties, as well as their renewable, non-toxic and biocompatible advantages. Natural plant gums can be easily modified by facile derivatization or a graft polymerization reaction to enhance the inherent properties or introduce new functions, thus obtaining new adsorption materials for the efficient purification of wastewater. This paper summarized the research progress on the fabrication of various gums-based adsorbents and their application in the decontamination of different types of pollutants. The general synthesis mechanism of gums-based adsorbents, and the adsorption mechanism of the adsorbent for different types of pollutants were also discussed. This paper was aimed at providing a reference for the design and development of more cost-effective and environmentally friendly water purification materials.

Adsorption behaviors and mechanisms by theoretical study of herbicide 2,4,5-Trichlorophenoxyacetic on activated carbon as a new biosorbent material

BackgroundAdsorption remediation is a low-energy water treatment technology based on removing different types of pollutants using the adsorption properties of a biosorbent. However, the biosorption of the pesticide 2,4,5-Trichlorophenoxyacetic on a plant named Ritama-Monosperma (L.) Boiss carbonized and activated by phosphoric acid as a new potential modern and eco-friendly biosorbent is the subject of this work. MethodsThe characteristics of the biosorbent are then determined utilizing several structural and textural characterization techniques such as XRD, FTIR, SEM/EDX, pHzpc, and Boehm titration. Batch adsorption tests were performed to investigate the impact of various parameters. However, the Freundlich, Languemir, Temkin, and Dubinin-Radushkevich models were employed to examine the experimental isotherm data. The density functional theory (DFT) modeling of 2,4,5-Trichlorophenoxyacetic has allowed us to discover the origin of the reactivity. Significant findingsAccording to biosorption kinetic data, the elimination of 2,4,5-Trichlorophenoxyacetic followed a pseudo-second-order response with a maximum adsorption capacity of 24.17 mg/g. The generalized isotherms demonstrated that the Freundlich isotherm best fitted the equilibrium data. The Thermodynamic study shows that pesticide biosorption is exothermic, spontaneous, and represents a decrease in randomness at the adsorbent-adsorbate interface, which is regulated by physisorption and happens as a result of electrostatic interactions, between the positively charged carbon surface at pH below 2.5, and the most nucleophilic centers C2, C5, C15, according to theoretical calculations, and pHzpc analysis.

PSYCHOLOGICAL FACTORS INFLUENCING PRO-ENVIROMENTAL ATTITUDES IN CHILDREN

One of the main requirements of modern society, and for the sake of its survival, is the formation of socially responsible behavior towards the greatly endangered environment. Every day we are faced with the problems of pollution, global warming, depletion of the ozone layer and many others. Therefore, it is of paramount importance to influence the youngest generations to develop attitudes that will develop a high awareness of the need to protect nature and how to treat it. In this sense, today, and for the sake of the future, we must actively work on the development of pro-environmental attitudes in children, which would manifest themselves in pro-environmental behavior tomorrow. The development of this cognitive component, that is, the attitude requires the society to instil in the child knowledge about nature, its benefits, but also its demands and the inseparability of man from it, which affects the child's affective relationship towards it, the feeling of attachment to the environment that becomes an integral part of values. With their conative component, attitudes also initiate individuals to act. This especially necessary during the current COVID-19 pandemic and the unresolved question of the origin of the virus. Was it created artificially in laboratories or is it of natural origin, as nature's response to man's relationship to it. Some studies show that children in the first grades of elementary school understand the phenomenon of environmental pollution, they even know about different types of pollution, but they still do not understand the causes of these events. Therefore, although there is not much research dealing with this problem, we consider it important to analyse current knowledge about the psychological factors influencing the development of pro-environmental attitudes in children.

Analyzing the effect of different types of pollution with bipolar complex fuzzy power Bonferroni mean operators

When any amount of harmful materials (any substance or any type of energy) is introduced into the climate at a rate quicker than it very well may be scattered or securely put away, then pollution occurs. These harmful materials are known as pollutants which can be natural and can also be manmade such as trash generated by factories. These harmful materials harm the quality of land, air, and water and cause various types of pollution, which affects the environment. In this article, we analyze the effect of various types of pollution on the environment and evaluate the most harmful type of pollution through an illustrative example by employing power Bonferroni mean (BM) operators in the setting of the bipolar complex fuzzy set (BCFS), like bipolar complex fuzzy (BCF) power BM (BCFPBM), BCF weighted power BM (BCFWPBM), BCF power geometric BM (BCFPGBM), and BCF weighted power geometric BM (BCFWPGBM) operators and a decision-making (DM) procedure created on these operators in the environment of the BCFS which are introduced in this article. Furthermore, we illustrate that the introduced operators and a DM procedure in the environment of the BCFS are more effective and have a wide model and advantages than certain prevailing works.

Adsorption of Toxic Tetracycline, Thiamphenicol and Sulfamethoxazole by a Granular Activated Carbon (GAC) under Different Conditions.

Activated carbon can be applied to the treatment of wastewater loading with different types of pollutants. In this paper, a kind of activated carbon in granular form (GAC) was utilized to eliminate antibiotics from an aqueous solution, in which Tetracycline (TC), Thiamphenicol (THI), and Sulfamethoxazole (SMZ) were selected as the testing pollutants. The specific surface area, total pore volume, and micropore volume of GAC were 1059.011 m2/g, 0.625 cm3/g, and 0.488 cm3/g, respectively. The sorption capacity of GAC towards TC, THI, and SMZ was evaluated based on the adsorption kinetics and isotherm. It was found that the pseudo-second-order kinetic model described the sorption of TC, THI, and SMZ on GAC better than the pseudo-first-order kinetic model. According to the Langmuir isotherm model, the maximum adsorption capacity of GAC towards TC, THI, and SMZ was calculated to be 17.02, 30.40, and 26.77 mg/g, respectively. Thermodynamic parameters of ΔG0, ΔS0, and ΔH0 were obtained, indicating that all the sorptions were spontaneous and exothermic in nature. These results provided a knowledge base on using activated carbon to remove TC, THI, and SMZ from water.

Toxicity Testing Organisms for Marine Ecotoxicological Research in China

Since the late 1970s, marine ecotoxicology began to sprout and develop in China. Based on the principles of dose-response relationships, some marine organisms are used in toxicity tests to evaluate the impact of marine pollutants on marine organisms and marine ecosystems. At the early stage, marine ecotoxicological research mainly focused on the bioaccumulation, biomagnification, and biodegradation of traditional pollutants such as heavy metals, radioactive elements, organotin, petroleum hydrocarbons, and pesticides, as well as their toxic effects on survival, growth, and other physiological indicators. With the development of Chinese industry, marine pollution has become increasingly serious. In addition to the traditional marine pollutants, toxicological research has been conducted on emerging pollutants with potential risks to marine ecosystems, such as POPs, emerging organic pollutants, nanomaterials, and microplastics. Moreover, the species of marine organisms used in toxicity testing have become more diverse. The selection of testing organisms is essential for evaluating toxicity correctly. The toxicity tests should be conducted on a variety of organisms from different trophic levels to ensure the comprehensive understanding of the impact of pollutants on marine ecosystems. The major types of marine organisms used in the toxicity testing include marine alga, protozoa, rotifera, annelida, mollusc, echinoderma, arthropoda, cephalopoda, and marine fish, which have been used in the toxicological studies of various marine pollutants. The outcome results can serve as the scientific basis for the ecological risk assessment of marine pollutants and the establishment of seawater quality criteria. It should be noted that the sensitivity of different testing organisms to different types of pollutants is quite diverse. Therefore, in addition to conducting a battery of tests on a variety of species which play important roles in marine ecosystems, elucidating the toxic mechanisms in different species is also important for marine ecotoxicological studies. The application of the above-mentioned organisms in marine ecotoxicology research in recent years is briefly reviewed here. Particularly, the six commonly used marine model species (Skeletonema costatum, Euplotes vannus, oysters, sea urchins, Tigriopus japonicus, and Oryzias melastigma) used in toxicity testing are introduced in detail.

Assessing wastewater pollution from outdoor night markets and its impacts on river quality.

Night markets are attractive tourist sites in Asian cities. However, the outdoor activities produce different types of pollutants. Air pollution and solid waste in night markets have received much attention, but wastewater pollution from night markets has rarely been examined. The untreated wastewater are discharged into roadside gutters and might contaminate receiving waterbodies. In this study, night markets in Taipei city, Taiwan, were surveyed to clarify the characteristics of wastewater. The sampled wastewater showed high levels of organic substances, oil and grease, and phosphorous but low levels of nitrogen compounds. In addition, the unit pollution loads in night market stalls were obtained. The BOD load of each stall in the night markets was 2,509 g/day, which is higher than the sewage emissions of 50 people. In order to know the impacts of night market wastewater on the receiving waterbody, a water quality model, the Water Quality Analysis Simulation Program (WASP), was used in the studied river, Keelung River. If night market wastewater could be collected (not discharged), the BOD concentration could be reduced by 9.8%, but the NH3-N and DO concentration could be reduced by less than 1%.

Pet cats, the better sentinels for indoor organic pollutants

Pets are the most intimate companions of humans, as pets and people share most of their lives indoors. Based on the connections between pet animals, humans, and the environment, pet cats and dogs are often recommended as sentinels for the detection of environmental contaminants and for comorbidity tracking. However, their suitability as sentinels is yet to be established. Persistent organic pollutants and environmental hormones have replaced particulate matter (PM2.5) and volatile organic compounds (VOCs) in causing indoor air pollution. This review summarises the differences in the types and concentrations of indoor organic environmental pollutants detected in pet dogs and cats. This includes an analysis of the main exposure routes of different types of pollutants. To identify which of the two pet species are better sentinels, cats and dogs were compared based on their metabolic capacities of various indoor organic pollutants. In addition to PM2.5, a range of organic compounds including polychlorinated biphenyls, polybrominated diphenyl ethers (PBDEs), bromophenols, perfluoroalkyl substances, organochlorine pesticides, fungicides, polycyclic aromatic hydrocarbons, phthalic acid esters, organophosphate pesticides, organophosphorus flame retardants, and melamine have been detected in both dogs and cats. Pets often accumulate PBDEs from dust; however, traces of PBDEs are present in their diet. The indoor pollutant contamination levels in internal cats were generally higher than those in dogs. Cats accumulate organic pollutants associated with indoor environments, but they are sensitive to their toxicity because, unlike dogs, cats cannot metabolise most of the accumulated pollutants. Moreover, cats share similar clinical symptoms of thyroid diseases in humans. Based on the above observations of detection of indoor organic pollutants, it could be said that cats are better sentinels than dogs.

Study on the Migration Law of Dissolved Organic Matter in Mine Water Treatment Station

With the improvement of coal-mining mechanizations and the intensification of human activities, the organic matter pollution of mine water is becoming severe. In this study, the chemical compositions of the influents and effluents from 15 mine water treatment stations in the mining area bordering Mongolia and Shaanxi were measured. The occurrence of DOM (dissolved organic matter) in the effluent from the mine water treatment stations in this area was determined by the EEM (excitation emission matrix), combined with the PARAFAC (parallel factor analysis) method. The DOM removal from the mine water treatment station in the Caojiatan coal mine is specifically discussed here, although trends are similar across the 15 mines. The treatment capacity of this treatment process for different types of pollutants is also evaluated, and a mine water treatment process suitable for the current coal-mining mode is suggested. The results show that the DOM of the mine water treatment stations in this area mainly has four components: a fulvic-acid-like substance (C1/C3), a protein tryptophan-like substance (C2), and a protein tyrosine-like substance (C4). The coagulation, filtration, and disinfection process has a removal efficiency of more than 90% for the protein-like tryptophan components, COD (chemical oxygen demand), and NO2−, and an efficiency of ~50% for TOC (total organic carbon), <30% for Cu2+ and F−, and almost no removal effect for protein-like tyrosine components, EC (electrical conductivity), TDS (total dissolved solids), and NH4+. These conclusions show that aliphatic hydrocarbons, such as alkanes and cycloalkanes, in mine water are removed by the treatment process, whereas macromolecular aromatic hydrocarbons and other groups are not removed by the treatment process. Based on this, an ozone-demulsification process for the special removal of protein tyrosine-like pollutants in mine water is proposed. This conclusion can provide theoretical support for research on the source and fate of the carbon trajectory in the water-cycle process and provides technical guidance for the removal of DOM from mine water.

Facile synthesis of Cu NPs@Fe3O4-lignosulfonate: Study of catalytic and antibacterial/antioxidant activities.

Environmental pollution is one of the important concerns for human health. There are different types of pollutants and techniques to eliminate them from the environment. We hereby report an efficient method for the remediation of environmental contaminants through the catalytic reduction of the selected pollutants. A green method has been developed for the immobilization of copper nanoparticles on magnetic lignosulfonate (Cu NPs@Fe3O4-LS) using the aqueous extract of Filago arvensis L. as a non-toxic reducing and stabilizing agent. The characterization of the prepared Cu NPs@Fe3O4-LS was achieved by vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD), scanning TEM (STEM), thermogravimetry-differential thermal analysis (TG/DTA), fast Fourier transform (FFT), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron (XPS) analyses. The synthesized Cu NPs@Fe3O4-LS was applied as a magnetic and green catalyst in the reduction of congo red (CR), 4-nitrophenol (4-NP), and methylene blue (MB). The progress of the reduction reactions was monitored by UV-Vis spectroscopy. Finally, the biological properties of Cu NPs@Fe3O4-LS were investigated. The prepared catalyst demonstrated excellent catalytic efficiency in the reduction of CR, 4-NP, and MB in the presence of sodium borohydride (NaBH4) as the reducing agent. The appropriate magnetism of Cu NPs@Fe3O4-LS made its recovery very simple. The advantages of this process include a simple reaction set-up, high and catalytic antibacterial/antioxidant activities, short reaction time, environmentally friendliness, high stability, and easy separation of the catalyst. In addition, the prepared Cu NPs@Fe3O4-LS could be reused for four cycles with no significant decline in performance.

MOF@biomass hybrids: Trends on advanced functional materials for adsorption

This contribution aims to demonstrate the scope of new hybrids between biomass and metal-organic frameworks (MOF@biomass) used in the adsorption process of pollutants. After a brief presentation of the use of the main series of MOFs as efficient adsorbents for different types of pollutants, the limitations of these structures related to particle size and hydrodynamic problems during their application are highlighted. Lignocellulosic biomasses are also recognized as an alternative adsorbent, mainly due to their high natural abundance and their low environmental impact during and after their application. The limited capacity of bioadsorbents becomes important in this research. Consequently, the largest amount of information existing in the last ten years on MOF-Biomass functionalization as a hybrid and improvement technology for adsorption processes is compiled, analyzed, compared and contrasted. So far, there is no evidence of works that exploit the concept of functionalization of adsorbents of different nature to give rise to new hybrid materials. Through this review it was found that the hybrids obtained show a higher adsorption capacity (Qe) compared to their precursors, due to the increase of organic functional groups provided by the biomass. Thus, for heavy metals, dyes, Arsenium anions and other organic and pharmaceutical compounds, there are increases in Qe of about 100 mg g−1. The possibility of the new hybrid being studied for desorption and reuse processes is also raised, resulting in a new line of research that is attractive for the industry from an economic and environmental point of view. The functionalization methods and techniques used in the studies cited in this article are outlined. In conclusion, this research brings a new horizon of study in the field of adsorption and mentions the main future challenges related to new sustainable applications.

Sonocatalytic degradation of ciprofloxacin and organic pollutant by 1T/2H phase MoS2 in Polyvinylidene fluoride nanocomposite membrane

The development of recyclable catalysts with effective properties and stable reusability is great importance for the removal of different types of pollutants in wastewater. Herein, we have synthesized Polyvinylidene fluoride (PVDF) polymer and mixed-phase 1T/2H MoS2 for immobilizing the sonocatalyst material. Techniques such as FESEM, XRD, FTIR, XPS, and UV–vis spectra have been used for analyzing the structural, and morphological properties. The formation of a 1T/2H mixed phase in MoS2 has been revealed by XRD and XPS analysis. Consequently, the sonocatalytic performance of the nanocomposite membrane was investigated through ciprofloxacin (CIP) and organic pollutants (Rhodamine B (RhB)). As a result, MoS2/PVDF (PM4) nanocomposite membrane exhibited a superior sonocatalytic activity with 94.37% and 84.37% of RhB and CIP degradation efficiency with pseudo-first-order kinetic constant (k) of 0.0187 min−1, and 0.0044 min−1. The sonocatalytic property of the nanocomposite membrane is related to 1T/2H mixed-phase and PVDF. Additionally, the metallic based 1T phase MoS2 helps to promote electrons and holes and reduce the recombination rate. Moreover, it promotes the generation of more hydroxy radicals (.OH), and superoxide radicals (∙O2−) play a significant role in sonocatalytic degradation of RhB pollutants. Thus, the improved sonocatalytic degradation of 1T/2H MoS2/PVDF composite membrane exhibited its application in real-time wastewater treatment.

On solute dispersion in an oscillatory magneto-hydrodynamics porous medium flow under the effect of heterogeneous and bulk chemical reaction

It is well known to all of us that there is a shortage of pure drinking water across the globe. Different types of pollutants (metallic and nonmetallic) mix with the water, and they cause several diseases such as cholera, typhoid, and various kinds of skin diseases, and even it is found that these kinds of particles may cause skin cancer. In the current study, an analytical solution of a two-dimensional convection–diffusion equation is obtained using Mei's multi-scale homogenization technique to investigate the influences of homogeneous and heterogeneous reactions on dispersion phenomena of the solute in an oscillatory magneto-hydrodynamics porous medium flow. In the appearance of the applied transverse magnetic field and oscillatory pressure gradient, a mathematical model of magneto-hydrodynamics dispersion between two parallel plates is presented. The analytical expressions of Taylor dispersivity, longitudinal mean and real concentration distributions, transverse concentration distribution, and transverse uniformity rate of the concentration are obtained. Also, the effect of various flow parameters such as Péclet number, Hartmann number, Schmidt number, Darcy number, oscillatory Reynolds number, porous parameter, dispersion time, downstream and upstream locations, chemical heterogeneous boundary reaction, and bulk reaction is discussed. How the transport phenomena of the solute display different natures with the various ranges of Darcy and Hartmann numbers with the aid of homogeneous and heterogeneous boundary reactions are highlighted. To show the effect of the absorption parameters on the transport coefficient, the third-order approximation of concentration is performed. It is seen that the dispersion coefficient (DT1) corresponding to the purely time-dependent flow increases with the enhancement of the Darcy number (Da). Moreover, it is found that as the Hartmann number (M) enhances, the total dispersivity (DT) decreases. Also, the transverse concentration distribution becomes flat for larger values of the Hartmann number. It is noticed that when Da≥1, the transverse variation curve turns into a trimodal distribution from a bimodal. This model may be helpful for separating various metallic and nonmetallic particles from the water to reduce the water pollution.

Control of organic contaminants in groundwater by passive sampling and multivariate statistical analysis

Organic contaminants in groundwater are among the most challenging chemical compound contaminants today, particularly when it comes to understanding their occurrence, origin, and relations in groundwater, as well as the transport processes, fate, and environmental impacts involved. This paper presents the use of active carbon fibre (AFC) passive sampling and multivariate statistical processing of the results to predict the possible occurrence of organic compounds (OCs) in groundwater and to determine the origin of various anthropogenic activity. This study aims to deepen our knowledge on the control of OCs in groundwater by introducing a multi-analytical and multi-elemental holistic approach, using the Dravsko polje aquifer, the largest intergranular aquifer in Slovenia, as an example. The occurrence of OCs in groundwater was determined by means of ACFs and compared against the characteristics of the recharge area and the type of compounds detected. We combined hierarchical cluster analysis (HCA) and principal component analysis (PCA) to identify the relationship between different OCs in groundwater. The relationships between their occurrence, environmental setting and type of compound were determined using multiple linear regression (MLR). From the total of 343 organic compounds detected using passive sampling, 47 were included in further statistical analysis. MLR shows that the environmental setting is one of the most important factors affecting the different types of pollutants in groundwater. MLR models were calculated for different sources of pollution (agricultural, urban, and industrial) based on the environmental setting, land use, agglomeration, infrastructure networks, and hydrogeological characteristics of the aquifer. By means of HCA and PCA, we identified the relationships between different OCs in groundwater. As expected, the strongest correlations were found between primary compounds and their degradation products (e.g. atrazine and desethylatrazine) and compounds of similar use (e.g. atrazine and propazine, also desethylatrazine and propazine, atrazine and simazine). Some of them were also found to have a similar molecular structure (e.g. palmitic and stearic acid, 5-methoxygramine and 5-methoxytryptamine). The use of the same substances in different environments (agricultural/urban) makes them markers of both (different) origins. Therefore, it is particularly important to determine the combination of markers of different origin using multivariate statistical methods, especially in the case of mixed land use. This study identifies the main factors influencing the distribution of groundwater OCs and thus contributes to a more comprehensive understanding of the vulnerability of shallow groundwater to surface-derived contamination in similar environments.

Recent Progress of Metal-Organic Frameworks and Metal-Organic Frameworks-Based Heterostructures as Photocatalysts.

In the field of photocatalysis, metal-organic frameworks (MOFs) have drawn a lot of attention. MOFs have a number of advantages over conventional semiconductors, including high specific surface area, large number of active sites, and an easily tunable porous structure. In this perspective review, different synthesis methods used to prepare MOFs and MOFs-based heterostructures have been discussed. Apart from this, the application of MOFs and MOFs-based heterostructures as photocatalysts for photocatalytic degradation of different types of pollutants have been compiled. This paper also highlights the different strategies that have been developed to modify and regulate pristine MOFs for improved photocatalytic performance. The MOFs modifications may result in better visible light absorption, effective photo-generated charge carriers (e−/h+), separation and transfer as well as improved recyclability. Despite that, there are still many obstacles and challenges that need to be addressed. In order to meet the requirements of using MOFs and MOFs-based heterostructures in photocatalysis for low-cost practical applications, future development and prospects have also been discussed.

Synthesis of a superhydrophilic coral-like reduced graphene oxide aerogel and its application to pollutant capture in wastewater treatment

Inspired by nature, a zeolitic-imidazolate framework-8@reduced graphene oxide (ZIF-8@rGO) aerogel was developed to remove tetracycline (TC) from water. The ZIF-8 nanoparticles grown on the rGO aerogel act like the many tentacles of a coral to hunt TC, and the rGO aerogel not only acts as a substrate but also acts like the belly of the coral, which can accommodate a large number of pollutants. Benefiting from these advantages, the ZIF-8@rGO aerogel can decontaminate TC, and showed an excellent adsorption capacity of 1776.26 mg g−1. Based on the experimental tests and characterization analysis, we speculated that the adsorption mechanism between TC and ZIF-8@rGO aerogel was mainly related to the hydrogen-bonding interactions, π-π interaction and electrostatic attraction. This discovery could be transformative for the removal of different types of pollutants by means of adjusting the functional groups of the materials and their composite technology.